They’re more expensive than regular domains, starting at $80 per domain name, and can only be purchased from approved registrars. The higher cost comes from add-ons that are automatically built into them: automatic daily virus scanning and other security features that are built into them.

Most businesses aren’t interested in building an adult-themed website, but many companies are buying the relevant domain for their business to tie them up and avoid someone purchasing “yourcompany.xxx” and forwarding it to a porn site.